CVE-2026-121553: medium-severity vulnerability in cotonti
Cotonti through 1.0.0 Predictable Validation Tokens via md5(microtime())
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.3epss 0.4%
Cotonti through 1.0.0 generates registration and email-change validation tokens with md5(microtime()), allowing attackers to bypass email-ownership verification by predicting tokens. Attackers can derive the generation time from the HTTP Date header and compute candidate tokens offline. They then submit these tokens to the users.register.php validate handler to activate accounts or confirm email addresses they do not control.
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Affected products
cotonti · cotontiReferences
https://github.com/Cotonti/Cotontihttps://github.com/Cotonti/Cotonti/blob/1.0.0/modules/users/inc/users.functions.php#L97https://github.com/Cotonti/Cotonti/blob/1.0.0/modules/users/inc/users.profile.php#L116https://github.com/Cotonti/Cotonti/blob/1.0.0/modules/users/inc/users.register.php#L148https://github.com/Cotonti/Cotonti/issues/1904https://github.com/Cotonti/Cotonti/pull/1905https://www.vulncheck.com/advisories/cotonti-through-1.0.0-predictable-validation-tokens-via-md5-microtime